BOILING HOUSE
EFFICIENCY
by
MUHAMMAD IQBAL QURESHI
DGM (Production)
1
Boiling House Efficiency


Boiling House Efficiency can be measured and
expressed by the crystallize-able sucrose
recovered in sugar % crystallize-able sucrose
available in Mixed Juice.
This is based on the practical finding that for
every part of non-sucrose present in the mixed
juice, a certain corresponding amount of sucrose
will be retained in the molasses when properly
exhausted.
Boiling House Efficiency (Cont.)

The non-crystallize-able sucrose in mixed
juice will vary according to the purity of
mixed juice, as juices of lower purity
(provided such low purities are not due to
cane deterioration) are usually associated
with a higher reducing sugar ash ratio,
which as we know helps to achieve better
exhaustion as salts have more affinity for
reducing sugars than for sucrose.
Boiling House Efficiency (Cont.)

It has also been found that after drought,
when the reducing sugars ash ratio is
exceptionally
high
through
cane
deterioration such juice would not respond
as stated.
Boiling House Efficiency (Cont.)

Viscosity retards the rate of crystallization
tremendously and As the boiling house of
any sugar mills is bound by limitation of
pans and crystallizers capacities such
deteriorated and viscous juice will lead to
a poor boiling house performance,
however high may be the reducing sugar
to ash ratio.
Boiling House Efficiency (Cont.)

Obviously, unusual high losses in the filter
cake or in the undetermined losses
through entrainment or inversion, also
lead to poor boiling house performance
excessive destruction of reducing sugar
during clarification by a too high pH will
also lead to poor boiling house
performance.
Boiling House Efficiency (Cont.)

It is therefore very much clear that if we are
talking about the boiling house efficiency we
should start from cane, because problem of
viscosity does not start in the factory itself but
it start much earlier. We cane see by checking
following factors. These factor must be
controlled.
1.
2.
Does the cane contain white tops?
Does the cane contain a lot of impurities such as
soil and other foreign matters?
Boiling House Efficiency (Cont.)
3.
4.
5.
6.
If the field was burned before harvesting, how long
has the cane remained in the field, before being
transported to factory ?
Has the stock been renewed daily i.e. cane stock in
factory yard must be cleared?
Is Mill sanitation a common practice i.e. application of
hot water jets and biocides.
Is the waiting tanks under juice tank is very large
preferably made conical bottom with less retention
time? At Matiari we eliminate the tank with help of our
juice stabilization system.
Boiling House Efficiency (Cont.)
7.
8.
Is the clarification of juice carried out without using
excessive lime? This year lime consumption is less as
compare to previous years.
Clarification process is well known to eliminate
impurities from Juice i.e. ash not eliminated in
Clarification. They will find their way into the final
molasses where over and above their weight, they are
going to maintain more sugar in solution. Ash increase
purity of mother liquor.
Boiling House Efficiency (Cont.)
8.
9.
PH meter must be very reliable and proper pH control
preferable auto-pH control correctly applied.
What is the purity of low grade Massecuite. Purity of CMassecuite should neither be too high, because
sufficient drop in purity will not be obtained; nor too
low because viscosity of Massecuite necessarily be very
high and difficulty of molasses separation in the
centrifugals; optimum purity of C-Massecuite for any
particular sugar factory could be obtained by plotting
the C-Massecuite versus final Molasses purity for past
seasons.
Boiling House Efficiency (Cont.)
10.
11.
The purity of C-Sugar should not be very low because
too much molasses and impurities are re-circulated
and crystallization is rendered very difficult because of
increasing viscosity of mother liquor, recycling
impurities increases volume of C-Massecuite.
Temperature of Massecuite at time of curing should
not be higher then 52 0C, which is considered the near
optimum temperature when curing very heavy density
Massecuite. If temperature will exceeds saturation
temperature crystals start dissolving.
Boiling House Efficiency (Cont.)
12.
Crystal size
Size of crystal in C-Massecuite should be
around 0.25 – 0.30 mm. However if
viscosity of Massecuite is not too high,
smaller grain will give better exhaustion
of molasses due to greater surface area
of crystal, best way to achieve required
crystal size is by true seeding using
slurry. Slurry should be uniform and
even.
Boiling House Efficiency (Cont.)
13.
Massecuite should contain crystals of the same
size and free from any false grain. False grain
blocks the passage of molasses and more
water will have to be used in centrifugal in
order to produce C-Sugar of required purity.
When false grain passes through the screens,
they contributes to increase in the purity of
final molasses. Same size crystals make curing
more easy at centrifugals.
Boiling House Efficiency (Cont.)
14.
15.
Massecuite should be free from Bagasse.
It prevents molasses from getting out of
the centrifugal screens. we have covered
our tanks.
Centrifugal screen should be examined
regularly and damaged screen should be
replaced at once.
IMPURITIES DEVELOPED AND
PROCESSING

As reducing sugars are destroyed or sucrose is
inverted due to high temperature we must pay
careful attention.


Minimum retention time. As at Matiari Sugar Mills Ltd
we used juice flow Stabilization system including flow
meter and auto level control eliminating the screen
juice tank at Mill house and weighing scale at process
house
Control of Exhaust and live steam temperature at
Evaporator and pan by auto de-supper heating
system.
IMPURITIES DEVELOPED AND
PROCESSING


Ensured
that barometric condensers are
working well i.e. Vacuum obtained is sufficiently
high to obtain a maximum boiling temp: of 65oC.
It is well known that froth fermentation, Maillard
Reaction b/w RS And lactic acid accelerated at
high temperature ,in which CO2 gas liberates.
Impurities introduced in the factory with lime
and water, good quality lime is used with
maximum CaO% i.e. more than 90% . Use of
condensate
for
imbibitions,
MOL
and
polyelectrolyte preparation.
TECHNIQUES





Pans must have good circulation and sufficient capacity,
we have used pan circulators in batch pans.
Appropriate cooling time must be given to Massecuite
before curing, especially “B” and “c” Massecuite.
Massecuite should be gravitate through crystallizers,
Massecuite heaters and centrifugal.
No dilution in Massecuite done.
Good pan work resulting Massecuite with required
crystal content high Brix as well as, well formed crystals
without false grain.
The Continuous Pan

The Continuous Pan has been increasing
interest of technologist because of rapid
increase in manufacturing cost. Economic
saving is expected by an increase in
throughput, by the reduction of downtime
associated with batch pans, when
stopping and starting and by an improve
steam consumption on the pan floor,
provided sufficient heating surface area is
available at evaporators to boil the pan
with later stage vapors.
The Continuous Pan




The Continuous Pan now provided fully automated and
continuous operations to cater for all Massecuite.
Owing to the use of effectively selected control
instruments, it will boil consistent quality “B” and “C”
Massecuite regularly.
With application of Radio Frequency PROBES “A”
Massecuite can be boiled without “False grain” to give
good quality “A” sugar of lower colour index.
Better steam economy can be achieved from the use of
continuous pan, operated on 2nd or 3rd vapor.
STRATEGY
B.
Microprocessor/Digital control is taking
over the technical control and monitoring
of process operation including pan
boiling to dominate human errors and
guard against deficiencies, and time lags
inherent in operation based controls.
Strategy for improvement in
performance
Increase in supply of improved cane variety
 Good cane preparation for utilization of Autocane preparation & feeding system
The philosophy of control is to ensure
constant and regular feeding of cane to cane
cutter (if installed), Fibrizer of Mills and at the
same time to avoid “chokes” . Mills setting of
a tandem is carried out for a planned daily
cane crushing

Strategy for improvement in
performance

For maximum extraction from the Mill
house a regular and Uniform cane feeding
is required. To ensure uniform cane
feeding,
PLC
(programmable
logic
controller) is installed, so that the speed
of carriers can be automatically controlled.
The PLC system helps in avoiding chokes.
STEPS TAKEN FOR IMPROVEMENT





Uniform Juice flow by flow meter and level
control at Mill House Juice tank. Therefore
avoiding waiting tank
Use of pH meter and Auto-control system by
the end of season
Use of 30 Mesh screen at MOL hopper and
regular cleaning of MOL tanks
Temperature of mud at vacuum filter is kept
80 0C. Mud tank and allied pipes lagged
Level of feed trough is controlled no overflow
is allowed to mud tank.
STEPS TAKEN FOR
IMPROVEMENT


Purity of cloudy and clear filtrate is checked at
regular basis because 1 degree drop in filtrate
purity from clear juice equivalent to a loss of
0.1% in BHR
Use of VFD and level transmitter at Massecuite
pump to save the power as well as crystal
breaking by overflow of Massecuite from pugmil
bottle stopped, because of level transmitter send
signal to VFD.
Modern Research


Modern Research shows that use of lime
saccharate for clarification is better than
milk of lime
In line Mixing is possible. Reaction takes
only 45 sec to complete
Results Of The Fine Tuning Jobs of
Boiling House


Improved Juice Clarification as compare to
last years, due to proper juice heating and
mud removal from Juice Clarifier as well
as maintaining Filter Cake temperature at
800C
Storage Tanks are covered to prevent
mixing of bagacillo
Fine Tuning Jobs of Boiling House




Muddy juice circulation stopped from
vacuum filter mud tray
New screen provided to vacuum filter #2
Bagacillo screen area increased
Purity drop of Clarified Juice to Filtrate is
reduced from 1.1 to 0.42
Fine Tuning Jobs of Boiling House

07 Nos. VFD installed at Process House
for Massecuite and Magma Pumps.






A-Massecuite, 02 Nos.
B-Massecuite, 01 No.
C-Grain, 02 Nos.
C-Massecuite, 01 No.
C-Magma, 01 No.
Benefits of VFD

Avoided recirculation and re-pumping of massecuite
causing grinding of Crystals hence controlling the
Massecuite level as well as power saving.
Fine Tuning Jobs of Boiling House





Continuous operation of C-Conti Pan
Control of purity drop between Massecuite and
Molasses especially in “C” to Final Molasses this
year remain 200 as compare to 170 and 180 for
last two seasons.
Proper cleaning of centrifugal backing screen
Proper control of C- Massecuite cooling and reheating
Use of condensate water for sugar drying in
radiators in place of steam.
Performance comparison
Season 201112
Season 2010-11
Season 200910
442261.637
441928.1
412513.1
Clarification Effect
10.87
9.52
10.08
Molasses percent Cane
4.61
4.56
4.5
Sugar loss in mol
1.41
1.43
1.42
N S % Primary Juice
4.1
3.92
3.85
NS TO Pol Ratio
27.65
26.04
25.48
Non-Sugar Removed
10.50
9.06
9.71
Lime Consumption % Cane
0.1124
0.1547
0.1291
20.19
18.62
17.13
0.42
1.09
Cane M T
Purity Drop from “C” mass: to F M
Purity Drop Clarified Juice to Filtrate
BH R
RBHR
87.03
92.14
1.2
86.91
86.80
91.75
91.80
Red. Boiling House Recovery
92.4
92.2
92
91.8
91.6
91.4
91.2
91
90.8
90.6
20042005
20052006
20062007
20072008
20082009
20092010
20102011
20112012
Boiling House Recovery
87.5
87
86.5
86
85.5
Boiling
House
Recovery
85
84.5
84
83.5
83
82.5
20042005
20052006
20062007
20072008
20082009
20092010
20102011
20112012
Primary NS Sugar Pol Ratio
40
35
30
25
20
15
10
5
0
1
6
11
16
21
26
31
Primary Non Sugar
Pol
Ratio 2009-10
36
41
46
51
56
61
66
71
76
81
Primary Non Sugar
Pol
Ratio 2010-11
86
91
96
101 106 111 116 121 126 131
Primary Non Sugar
Pol
Ratio 2011-12
NS Removal %
16
14
12
10
8
6
4
2
0
1
6
11
16
21
26
31
36
41
46
51
2009-10
56
61
66
71
76
2010-11
81
86
91
96
2011-12
101 106 111 116 121 126 131
Molasses % Cane
6
5
4
3
2
1
0
1
6
11
16
21
26
31
36
41
2009-10
46
51
56
61
66
2010-11
71
76
81
86
91
2011-12
96
101 106 111 116 121 126 131
Loss in Final Molasses % Cane
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1
6
11
16
21
26
31
36
41
46
51
2009-10
56
61
66
71
76
81
2010-11
86
91
96 101 106 111 116 121 126 131
2011-12
Loss in V.F % Cane
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
1
6
11
16
21
2009-10
26
31
36
41
46
51
56
61
66
2010-11
71
76
81
86
91
96 101 106 111 116 121 126 131
2011-12